Letter to the Editor: Fasting plasma glucose associated with mortality rate in T2DM patients with COVID-19 infection.

Dear Sir,

Since December 2019, a novel coronavirus outbreak occurred in Wuhan and quickly spread to other parts of China as well as all over the world. It was reported that diabetes might be associated with higher risk of mortality among severe COVID-19 cases [1,2].

To investigate the clinical course and outcomes of patients with type 2 diabetes (T2DM) and COVID-19, we collected data from five designated hospitals between January 3th, 2020 and February 3th, 2020, in Wuhan, China. A total of 47 patients were included in the analysis.

The median age of these patients was 61.00 years (range, 38–95 years), and 23 (48.94%) were male. Slightly more than half (n = 25; 53.19%) had at least another chronic comorbidity, besides diabetes. For the primary outcome, among these patients, 9 (19.15%) patients had died, due to the development of organs dysfunction. Seven of these nine (77.78%) patients were male. The median duration from admission to death was 7.00 (range, 2–19 days) days in the non-survivors. Compared with survivors, non-survivors were older (80.00[range, 49–95 years] vs. 60.50[range, 38–91 years]), and were more likely to have chronic medical illnesses (66.67% vs. 50.00%). Palpitation (44.44% vs 2.63%) were more likely to be reported by non-survivors. Moreover, our data showed lymphocytopenia occurred in 30 (63.83%) patients, with a significant decrease (0.60[0.57,0.72] vs.0.96[0.63,1.25]) in non-survivors. Both total bilirubin (12.70[8.90,24.00] vs. 9.03[6.40,11.55]) and direct bilirubin (8.46[3.65,13.85] vs. 3.00[2.43,4.25]) were significantly increased in non-survivors. These were accompanied by significantly prolonged prothrombin time (14.00[13.60,16.20] vs. 12.80[11.85,14.05]) and increased D-dimer concentration (1.54[1.23,4.83] vs. 0.56[0.31,0.92]). On the other hand, elevated blood urea nitrogen (6.51[5.10,8.71] vs. 4.67[3.75,6.42]), serum creatinine (Cr) (96.50[80.00,101.00] vs. 71.00[54.00,81.00]), and decreased eGFR (65.20[53.38,75.72] vs. 91.60[72.19,106.89]) were observed in non-survivors compared to survivors. These observations were associated with increased serum potassium concentration (4.17[3.78,4.57] vs. 3.82[3.54,3.99]) in non-survivors. No statistical differences in the four parameters relating to blood lipids were found between survivors and non-survivors. Medications for treatment of T2DM or COVID-19 were not different between survivors and non-survivors. Additionally, a Cox regression model was applied to evaluate the time-dependent hazards of developing death, finding that age, FPG, and total bilirubin concentration represented the highest risk factors for non-survival in diabetic patients with COVID-19. (See Table 1 )

Table 1

Cox regression model for identifying risk factors for death in diabetic patients with confirmed COVID-19.

Variables	Univariate			P value	Multivariate			P value
	OR	LL	UL		OR	LL	UL
Age	1.06	1.01	0.11	0.02	1.36	1.06	1.75	0.02
Gender (male)	0.28	0.06	1.33	0.11
CKD	0.16	0.02	1.33	0.09
Respiratory diseases	4.17	0.85	20.48	0.08
Fasting plasma glucose	1.10	1.03	1.18	0.01	1.52	1.06	2.17	0.02
Leucocytes	1.22	0.96	1.56	0.11
Hemoglobin	1.00	0.96	1.03	0.77
Neutrophils	1.23	0.99	1.53	0.06
Lymphocytes	0.15	0.18	1.25	0.08
Total bilirubin	1.09	1.03	1.15	0.01	1.65	0.95	1.20	0.01
eGFR	0.97	0.94	1.00	0.02	1.07	0.98	1.16	0.14
K+	3.05	0.94	9.87	0.06
Ca2+	0.03	0.00	2.34	0.11
C-reative protein	1.01	0.99	1.02	0.52
D-dimer	1.07	1.02	1.13	0.01	1.07	0.95	1.20	0.30
Fibrinogen	0.82	0.50	1.36	0.45

Our study has several limitations. First, the sample size is limited. Second, this is a retrospective study, and some specific information related to diabetic state was not collected on admission, such as HbA1C, and duration of diabetes. However, the data in this study permit a preliminary assessment of the clinical course and outcomes of diabetic patients with COVID-19. Most importantly, this study indicated that older T2DM patients with poor control of fasting plasma glucose and elevated total bilirubin are at increased risk of death.

Further efforts are still needed to collect more data on both patients with diabetes and those without diabetes to better characterize the clinical features of patients with diabetes and COVID-19, and inform the best treatment strategy to reduce the possibility of becoming critical cases and improve the prognosis [3].

Declaration of competing interest

None.